1. Field of the Invention
The present invention relates to enhancing the efficiency of electric drive systems and particularly to the provision of a direct current powered drive system suited for use in an environment, such as an electrically powered vehicle, where operating power is derived from storage batteries subject to periodic recharge. More specifically, this invention is directed to a flywheel type drive wherein energy for initiating and maintaining the rotation of a flywheel mechanism is furnished by an electric motor or motors. Accordingly, the general objects of the present invention are to provide novel and improved methods and apparatus of such character.
2. Description of the Prior Art
While not limited thereto in it utility, the present invention is particularly well suited for employment in electrically powered vehicles. As petroleum and natural gas reserves dwindle, increasing attention is being directed to electrically powered vehicles. While electrically powered vehicles were at one time widely used, such vehicles drastically declined in popularity when the availability of inexpensive petroluem products became widespread. Despite renewed interest in the electrically powered vehicles in recent years, there has in fact been little progress made in developing a practical "electric". Thus, available electrically powered vehicles, the conventional golf cart type vehicle presently being the most often used variety of such vehicle, are characterized by a number of inherent deficiencies. The single deficiency which constitutes the principal impediment to widespread usage is lack of range. This lack of range results from the rather high power drain imposed on the bank of storage batteries which must presently be utilized as the power source. This power drain, to a large measure, results from the substantial weight of the conventional lead-acid type battery which is employed in the power supply. Thus, a cruising range in excess of 25 miles, with a reasonable margin of reserve, can not presently be achieved in an electrically powered vehicle of accpetable size for everyday use because of the excessive demands imposed on the bank of storage batteries largely as a consequence of the weight of those batteries.
In recent years attempts have been made to improve the cruising range of electrically powered vehicles through use of lightweight materials in the vehicle body and chassis and by resort to aerodynamic styling. These efforst have had some limited success. Attempts to develop power sources which could be used in place of the conventional heavy lead-acid storage battery have to date been totally unsuccessful. As evidenced by the present inventor's U.S. Pat. No. 3,562,567, effort has also been devoted to improving the efficiency of the drive systems which convert the potential energy of the storage batteries to the kinetic energy of the drive shaft. Such efforts to improve drive system efficiency, particularly techniques which have employed flywheel type drives, have been moderately successful. However, since it remains necessary to rely upon heavy storage batteries as the power source, further improvements in drive system efficiency are required.